Decolorized and stabilized organic polyisocyanate compositions



United States Patent 0 3,260,702 DECOLORIZED AND STABILIZED ORGANIC POLYISOCYANATE COMPOSITIONS Tomohisa Murakami, Kanagawa-ken, Shinichi Morisaki,

Yokosuga-shi, and Koshiro Hiiro, Yokohama, Japan,

assignors to Hodogaya Chemical Co., Ltd., Tokyo,

Japan, a corporation of Japan No Drawing. Filed June 4, 1963, Ser. No. 285,197

11 Claims. (Cl. 260-77.5)

This invention relates to decolorized and stabilized organic polyisocyanates prepared by adding to an organic polyisocyanate 0.001 to 1% by weight, based on the weight of the organic polyisocyanate, of a material selected from the group consisting of compounds containing 1 to 4 ethyleneimine rings in the molecule.

At present, organic polyisocyanates are used in large amounts in the field of synthetic chemistry as the starting materials for coatings, foams, elastomers and the likes. Although they are colorless immediately after production, most of the organic polyisocyanates tend to become colored during storage or during the steps of reacting them with materials having active hydrogen, such as alcohols, amines or water. Various processes for preventing organic polyisocyanates from such coloring have been patented and announced, but none of the processes has been sufficiently satisfactory for the stabilization of organic polyisocyanates, which particularly tend to be colored.

In order to prevent organic polyisocyanates from coloring, the present inventors have investigated the coloration-preventing actions of various materials on organic polyisocyanates to find that most of the materials containing ethyleneimine rings prevent them from coloring. Particularly, it has been discovered that not only the majority of the materials containing ethyleneimine rings prevent organic polyisocyanates from coloring but the addition of a minute amount of said materials enables colored organic polyisocyanates to be decolorized, without injuring the original quality of the organic polyisocyanates, which has conventionally been considered impossible. It has also been found that, in synethesizing polyurethane or polyurea compounds from organic polyisocyanates and compounds having a plurality of hydroxyl or amino groups, the addition of the materials containing ethyleneimine rings or the use of organic polyisocyanates to which said materials have been added makes it possible to form less colored or difficultly coloring polyurethane or polyurea compounds.

Therefore, an object of the present invention is to prevent organic polyisocyanates from coloring during storage.

Another object is to decolor colored organic polyisocyanates.

A further object is the synthesize less colored or difficu-lty coloring polyurethane or polyurea compounds from organic polyisocyanates and compounds having a plurality of hydroxyl or amino groups.

There are very many materials containing etheyleneimine rings which are usable for the above objects. It is rather difiicult, according to the experiments conducted by the present inventors, to find ethyleneimine ring-containing materials having no coloration-preventing or decoloring action. These materials have the following general formulas, wherein R is a lower alkyl, cycloalkyl, aryl, or aralkyl group; R- is a lower alkylene, cycloalkylene, arylene, or aralylene group; X is O, S or NH; Y is O or S; and

3,260,702 Patented July 12, 1966 represents an ethyleneimine ring. Compounds containing one ethyleneimine ring include:

Compounds containing three or more ethyleneimine rings include:

The present inventors selected as typical compounds of those having the above formulas, 33 ethylene-iminecontaining compounds shown in Table l and examined 45 the coloration preventing and decolorizing actions thereof on organic polyisocyanates. The results are shown below.

TABLE 1 O (l) l-ethylethyleneimine:

(2) Diethyleneiminophenylmethane:

(3 l-benzylethyleneimine:

(4) w,w-p-Xylylenediethyleneimine:

( N-phenyl-N'-ethyleneurea:

P h-NH c 0 N3 (6) N-cyclohexyl-N'-ethyleneurea:

NHO 0N l (7) N-octyl-N'-ethyleneurea:

CaHnNH C ON I (8) 1,6-hexamethylenebisethyleneurea:

DNCONH (CHQMNHOONj (9) 2,4-tolylenebisethyleneurea:

NHCONJ I IHC 0 Ni] (10) 4,4'-dipheny1methanebisethyleneurea:

( 1 l) N-phenyl-N'-ethylenethiourea:

Ph-NHC 8N3 12) N-cyclohexyl-N-ethy1enethiourea:

@NHC SNj 13 l-acetylethyleneimine:

C H30 (0) N3 (14) l-benzoylethyleneimine:

PhC (0)N I (15 Adipobis 1 -ethyleneimine) H 0 (16) Terephthalobis l-ethyleneimine) (21) Bisl-ethyleneimino) -phenoXyphosphine-oxide:

@ K QZ (22) Bis(1-ethyleneimino) phosphoxy anilide:

(Bdr -Q 4 (23) Pyrophosphoric acid tetraethyleneimine:

N P (0) OP (0) N\ 2 24) EthyIeneglycol-bis (diethyleneiminophosphate) (26) Bis-(l-ethyleneimino)butoxyphosphine sulfide:

(27 1,4-Cyc10hexanediol-bis (diethyleneiminothiophosphate) (28) Ethyleneglycol-bis (diethyleneiminothiophosphate) (29) Ethylphosphonic acid diethyleneimine:

(30) Phenylphosphonic acid diethyleneirnine:

(31) Phosphorous triethyleneimine:

(32) ButoXy-bisl-ethyleneimino -Syrn-triazine:

)P (S) O OHzOHzO P (S) 2 D t N f 0 C4110 (3 3) CycloheXylamino-bis-( l-ethyleneimino) -S-triazine:

Generally, the suitable amount of decolorizing and stabilizing agents to be added to organic polyisocyanates is 0.0011%, preferably 0.010.5% by weight, based on the weight of the organic polyisocyanates, though it varies depending on the kind of organic polyisocyanates, degree of color thereof, kind of said agent used and storage conditions of organic polyisocyanates. These decolorizing and stabilizing agents may be added singly, but their coloration-preventing eifect is frequently increased when they are used in combination with hydroxyaryl compounds or alkylor val koxy-substituted hydroxyaryl compounds, which have conventionally been known as coloration preventing agents, such as, for example, p-cresol, 4,4-dioxydiphenyl, 2,6-di te rt-b utyl-4=methylphenol, 2,6-di-tert-butylmethoxyphenol, 4,4 dioxydiphenylmethylethylmethane, bis-(2-hydroxy-3-tert-butyl-5-methylphenyl) methane, hydroquinone and py-rogallol. In this case, the preferable amount of hydroxyaryl compounds or alkylor alkoxysubstituted hydroxyaryl derivatives to be added is 0.01 to 0.5% by weight based on the weight of organic polyisocyanates.

The decolorizing and stabilizing agents of the present invention are effectively employed for many organic polyisocyanates but mainly for those shown below:

1 ,4 -tetramethylene diisocyanate 1,6-hexamethylenediisocyanate 1,4-cyclohexanediisocyanate w,w'-m-Xylylenediisocyanate w,w-p-Xylylenediisocyanate 1 ,3 -phenylenediisocy anate Chlorobenzene-2,4-diisocyanate 2,4-tolylenediisocyanate Any mixtures of 2,4-tolylenediisocyanate and 2,6-tolylenediisocyanate. 4,4-rnethylenebis (phenylisocyanate) 4,4-diphenyldiisocyanate 4,4-diphenyletherdiisocyanate 1,S-naphthylenediisocyanate The present decolorizing and stabilizing agents are also effective for the decoloration and prevention of coloration of organic polyisocyanates having terminal isocyanate groups which have been synthesized from organic diisocyanates and water, organic diamino compounds or polyhydric alcohols, such as trimethylol propane, butanediol, polyether polyol, or polyester polyol.

The effect of the present decolorizing and stabilizing agents will be illustrated with reference to the following examples.

Although certain preferred embodiments of the invention have been disclosed for purpose of illustration, it will be evident that various changes and modifications may be made therein without departing from the invention.

Example 1 Thirty-three samples each of ml. of 4,4'-methylenebis(phenylisocyanate), which had been colored to 250 measured in terms of A.P.I-I.A. number (unit measured on the Hazen (cobalt-platinum) scale as determined by the method described on pages 87-89 of Standard Methods for the Determination of Water, Sewerage, and Industrial Wastes (10th edition, 1955, published by the American Public Health Association) were charged into colorless ml. ampoules. 0.003 g. of each material shown in Table 1 was added to respective ampoules, which were then sealed. After thorough mixing, the ampoules were stored in a dark place at C. to examine the varia-tion in the degree of coloration. The results are shown in Table 2, in which the numbers of respective additives represent those of the compounds shown in Table 1, and 0 shows the case where no material was added.

TABLE 2 Degree of coloration Time (hn) N0. of additive Example 2 a dark place at 40 C. to examine the relation between the 75 basis of 70 storage time and the variation in degree of coloration. The results are shown in Table 3, wherein the numbers of ethyleneimine derivatives represent those of the compounds described in Table 1.

IABLE 3 Additives Time (hr.)

Amount Nos. of Amount of of 2,6- -ethylenederivative di-tertimine added butyle 1 24 100 1,000 deriva- (g.) eresol tives added As is clear from the above examples, most of the materials containing ethyleneimine rings in the molecules are excellent, even when used in a minute amount, in decolorizing and coloration-preventing effects on organic polyisocyanates. However, these effects difier more or less depending upon the kind of organic polyisocyanates to be treated. The experiments of the present inventors show that, amoung the compounds set forth in Table 1, those with the numbers of 3, 4, 19, 21, 23, 26, 27, 29, and 31 are excellent. However, by increasing the addition amount, other ethyleneimine derivatives than the above compounds are also usable as commercially valuable modifying agents.

Example 3 100 parts of polytetramethylene ether glycol having a hydroxyl value of 106 were heated to 100 C. and dried in vacuum, while stirring, for one hour at 3 mm. Hg. To the resulting material, 38.2 parts of 4,4'-methylenebis (phenylisocyanate) were added to react therewith for 10 minutes. To the reaction product, 52 par-ts of tetramethylene glycol were added and the resulting mixture was thoroughly stirred to form, about 5 minutes later, a homogeneous viscous material. This material was poured into a vessel, to which a silicone backing had been applied, and allowed to stand in a heater at 130 C. for about 3 hours to form an elastomer free from plasticity. Subsequently, a suitable amount of the elastomer was cut and weighed in an iron mold to which a silicone backing had been applied. After preheating to C., the elastomer was subjected to compression molding for 15 minutes at 100 kg./cm. by use of a hot press heated to 160 C. to obtain a yellow brown, translucent, elastic shaped article. The same operations as above were repeated using as a starting material 4,4 methylenebis (phenylisocyanate) decolor-ized and stabilized with the addition of 0.01% of: tris-(l-ethyleneimine) phosphine oxide, whereby a light yellow-brown shaped article was obtained. Thus, the effect resulting from the addition of the decolorizing and stabilizing agent is marked.

Example 4 73 g. of tolylene diisocyanate (an 80/20 mixture of 2,4- and 2,6-isomers) were added to a mixture comprising 1 21 g. of a propylene oxide addition-product of trimethylolpropane having a hydroxyl value of 413, 0.75 g. of d-ibutyltindilaurate, 1.2 g. of a surface active agent (siloxane-oxyalkylene polymer) and 35.5 g. of triohloro monofluoromethane, while thoroughly stirring the latter mixture. Immediately after the initiation of foaming, the resulting mixture was charged in a mold and heated to 70 C. for 30 minutes to obtaion a white rigid foamed 7 material with a density of about 0.03 g./cm. When exposed directly to the sun for one month, the foamed material was colored to yellow brown. The same operations as above were repeated, using as a starting material It'olyl'enediisocyanate which had been decolorized and stabilized with the addition of ethyleneglycol bis-(diethyleneimino thiophosphate) in an amount of 0.01% by Weight, to obtain a rfoamed material. Even when allowed to stand under the same conditions as above, the foamed material was only slightly colored. Thus, the effect derived from the addition of the decolorizing and stabilizing agent is conspicuous.

What we claim is:

1. A decolorized and stabilized organic polyisocyanate composition which comprises an organic polyisocyanate and 0.001 to 1% by weight, based on the weight of the organic polyisocyanate, of a material selected from the group consisting of compounds having the general formulas of RN RC(Y)N I, RXC(Y)N/), (RX)zP(Y)N wherein R is selected from the group consisting of lower alkyl, cycloalkyl, aryl and aralkyl groups, R is selected from the group consisting of lower alkylene, cycloalkylene, arylene and ar-alkylene groups, X is selected from the group consisting of O, S or NH, Y is selected from the group consisting of O or S and represents an ethyleneimine ring.

2. A decolorized and stabilized organic diisocyanate composition which comprises an organic diisocyanate represents an ethyleneimine ring.

6. A decolorized and stabilized 4,4-methylenebis (phenylisocyanate) which comprises a 4,4-methylenebis (phenylisocyanate) and 0.001 to 1% by weight, based on the weight of the 4,4-methylenebis (phenylisocyanate),

of a material selected pounds represented by from the group consisting of comthe molecular formulas D -s t d B 1 it N an N\ N O NH C4119 wherein 3 represents an ethyleneimine ring.

7. A decolorized and stabilized organic polyisocyanate composition which comprises an organic polyisocyanate, 0.001 to 1% by weight, based on the weight of the organic polyisocyanate, of a material selected from the group consisting of compounds having the general formulas of wherein R is selected from the group consisting of lower alkyl, cycloalkyl, aryl and aralkyl groups, R is selected from the group consisting of lower alkylene, cycloalkylene, arylene and aralkylene groups, X is selected from the group consisting of O, S or NH, Y is selected from the group consisting of O or S and represents an ethyleneimine ring and 0.01 to 1% by weight, based on the weight of the organic polyisocyanate, of a material selected from the group consisting of hydroxyaryl compounds and alkyland alkoxy-substituted compounds thereof.

8. A composition as described in claim 7 wherein the third members are selected from the group consisting of p-cresol, 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl- 4-methoxyphenol, 4,4-dioxy-diphenylmethylethylrnethane, bis(2-hydroxy-3-tert butyl-5-methylphenyl)methane, 4,4- dioxydiphenyl, hydroquinone, and pyrogallol.

9. A method for proventing the coloration of organic polyisocyanates which comprises adding to an organic polyisocyanate 0.001 to 1% by weight, based on the weight of the organic polyisocyanate, of a material selected from the group consisting of compounds having the general formulas of wherein R is selected from the group consisting of lower alkyl, cycloalkyl, aryl and aralkyl groups, R is selected from the group consisting of lower alkylene, cycloalkylene, arylene and aralkylene groups, X is selected from the group consisting of O, S or NH, Y is selected from 10 the group consisting of O or S, and N represents an ethyleneimine ring.

10. A method for decolorizing organic polyisocyanates which comprises adding to an organic polyisocyanate 0.001 to 1% by weight, based on the weight of the organic polyisocyanate, of a material selected from the group consisting of compounds having the general formulas of wherein R is selected from the group consisting of lower alkyl, cycloalkyl, aryl and aralkyl groups, R is selected from the group consisting of lower alkylene, cycloalkylene, arylene and aralkylene groups, X is selected from the group consisting of O, S or NH, Y is selected from the group consisting of O or S, and

represents an ethyleneimine ring.

11. In a method for synthesizing a polyurethane compound from an organic polyisocyanate and a compound having a plurality of hydroxyl groups, an improvement for the production of a less colored polyurethane compound characterized by adding to the organic polyisocyanate 0.001 to 1% by weight, based on the weight of the organic polyisocyanate, of a material selected from the group consisting of compounds having the general formulas of the group consistin the group consistin g of O, S or NH, Y is selected from g of O or S, and

represents an ethyleneirnine ring.

References Cited by the Examiner UNITED STATES PATENTS Voorhees 252-401 Bestian 260239 Bortnick 260239 Spiegler 260453 Vierling 252403 MacKinney 260239 LEON J. BERCOVITZ, Primary Examiner. 20 M. C. JACOBS, Examiner. 

1. A DECOLORIZED AND STABILIZED ORGANIC POLYISOCYANATE COMPOSITION WHICH COMPRISES AN ORGANIC POLYISOCYANATE AND 0.001 TO 1% BY WEIGHT, BASED ON THE WEIGHT OF THE ORGANIC POLYISOCYANATE, OF A MATERIAL SELECTED FROM THE GROUP CONSISTIN OF COMPOUNDS HAVING THE GENERAL FORMULAS OF
 11. IN A METHOD FOR SYNTHESIZING A POLYURETHANE COMPOUND FROM AN ORGANIC POLYISOCYANATE AND A COMPOUND HAVING A PLURALITY OF HYDROXYL GROUPS, AN IMPROVEMENT FOR THE PRODUCTION OF A LESS COLORED POLYURETHANE COMPOUND CHARACTERIZED BY ADDING TO THE ORGANIC POLYISOCYANATE 0.001 TO 1% BY WEIGHT, BASED ON THE WEIGHT OF THE ORGANIC POLYISOCYANATE, OF A MATERIAL SELECTED FROM THE GROUP CONSISTING OF COMPOUNDS HAVING THE GENERAL FORMULAS OF 